R/S ratio calculation

I have B-cell receptor sequencing data processed with MiXCR, where I exported the clones files which contain information about SHM on both nucleotide (nt) and amino acid (aa) levels.

I am looking into calculating replacement-to-silent ratio (R/S) of SHMs using the information provided in my MiXCR clones files.

Does anyone has an idea about the best way to go around it? or maybe using a different tool?